1. Field of the Invention
The present invention generally relates to the field of display technology, and more specifically to an anti-peeping device for a display device and a control method for the anti-peeping device.
2. Description of the Related Art
At present, a conventional anti-peeping device or anti-peeping film is based on a grating that blocks light at certain angles, so that a user can watch contents output by a display device only at an allowed range of viewing angle. If a user stands out of the allowed range predetermined during manufacture of the anti-peeping device, he/she will not be able to watch the contents of the display device.
For example, an existing anti-peeping device is shown in FIG. 1. The anti-peeping device comprises a plate-shaped substrate 1, and a plurality of light blocking walls 2 fixed on the plate-shaped substrate 1. Each of the light blocking walls 2 is disposed perpendicularly to the plate-shaped substrate 1. As shown in FIG. 1, depending on the way in which each of the light blocking walls 2 is disposed, a region between a sightline a and a sightline b is an allowed watching region, and a region at the left side of the sightline a and a region at the right side of the sightline b are unallowed watching regions. Users standing in the allowed watching region can view at least parts of the content from a display device, and users standing in the unallowed watching region cannot view the content from the display device totally or at least cannot view the content from the display device clearly.
In another example, as shown in FIG. 2, a plurality of light blocking walls 2 are fixed on the plate-shaped substrate 1, and each of the light blocking walls 2 is inclined towards the left side, so that it forms a sharp angle to the left side of the plate-shaped substrate 1, and forms an obtuse angle to the right side of the plate-shaped substrate 1. As shown in FIG. 2, depending on the way in which each of the light blocking walls 2 is disposed, a region between a sightline a and a sightline b is an allowed watching region, and a region at the left side of the sightline a and a region at the right side of the sightline b are unallowed watching regions. Users standing in the allowed watching region can view at least parts of the content from a display device, and users standing in the unallowed watching region cannot see the content from the display device totally or at least cannot view the content from the display device clearly.
In a further example, as shown in FIG. 3, a plurality of light blocking walls 2 are fixed on the plate-shaped substrate 1 and each of the light blocking walls 2 is inclined towards the right side, so that it forms a sharp angle to the right side of the plate-shaped substrate 1, and forms an obtuse angle to the left side of the plate-shaped substrate 1. As shown in FIG. 3, depending on the way in which each of the light blocking walls 2 is disposed, a region between a sightline a and a sightline b is an allowed watching region, and a region at the left side of the sightline a and a region at the right side of the sightline b are unallowed watching regions. Users standing in the allowed watching region can view at least parts of the content from a display device, and users standing in the unallowed watching region cannot view the content from the display device totally or at least cannot view the content from the display device clearly.
From the above examples, the inventor finds that, since the light blocking walls 2 are fixedly attached to the plate-shaped substrate 1, the angle formed between each light blocking wall 2 and the plate-shaped substrate 1 is fixed. That is to say, a light blocking angle of each light blocking wall 2 is fixed, and the allowed watching region and the unallowed watching regions are also fixed. If a user wants to change the allowed watching region and the unallowed watching regions, he or she has to replace the anti-peeping device with another one of a different type.
Therefore, safety and applicability of current anti-peeping devices are poor, and users have to buy different anti-peeping devices, which leads to a high cost.